What is Weep Hole? Weep holes in retaining wall detail

What is a weep hole?

Weep holes are small openings in the RCC wall or retaining wall to prevent the wall from accumulating pore water pressure. It is provided generally at the bottom of the wall. If the backfill of the wall is more than the weep holes are provided up to the height of the soil filled.

In the rainy season, water in the soil gets accumulated at the backside of the retaining wall. Due to this retaining wall have to face an extra load on the side face of the wall.

So, Sometimes retaining walls collapse due to active and passive earth pressure due to soil. To prevent this collapsing weep holes are provided.

Weep holes in the retaining wall are provided to drain water collected at the back of the retaining wall. The weep hole in the retaining wall may be circular or rectangular in shape.

Here you will see the distance between weep holes, how they are provided etc in weep holes in retaining wall detail below.

Distance between two weep hole

What is Weep Hole? Weep holes in retaining wall detail

A weep hole in the retaining wall may be dangerous in terms of crack. The distance between two weep holes should not be more than one meter. If the distance between two weep holes is less than one meter then there may be cracks in the wall.

The weep hole in the retaining wall should not be in the same line it should be in the Zig-Zag position as shown in the figure below.

What is Weep Hole? Weep holes in retaining wall detail

Failure of retaining wall

If we do not provide a weep hole in the retaining wall then the wall may fail in two ways.

  1. Failure due to sliding:- The failure of the Retaining wall due to changing the position of the wall in the direction of stress due to active and passive earth pressure is known as failure due to sliding.
  2. Failure due to Overturning:- The failure of the Retaining wall due to rotation of the wall about its base the wall due to active and passive earth pressure is known as failure due to overturning.

How to provide weep hole?

What is Weep Hole? Weep holes in retaining wall detail

Weep holes are provided between the reinforcement in the retaining wall. The round or rectangular plastic (PVC) pipes are provided throughout the thickness of the retaining wall. Generally, the diameter of the weep holes is kept from about 10 cm to 15 cm according to the size of the wall.

Read more,

Type of wall | Load Bearing, Non Load bearing, Retaining wall, Shear Wall

How to backfill a retaining wall | Best backfill material for retaining wall

Cantilever retaining wall | Parts, Types, and Design of Cantilever Wall

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"Structural Engineer" with over 5 years of experience in estimation, structural design, and surveying. I am passionate about using his skills to create safe and sustainable structures. I am also a keen writer, and I enjoy sharing my knowledge and experiences with others.